1. Technical Field
This invention relates to slider-suspension assemblies for data recording information storage systems and to a method for making such assemblies. In particular, the invention relates to an improved suspension for a magnetic disk drive system and method for electrically connecting the suspension to actuator arm leads or an electronic package.
2. Description of the Related Art
Information storage devices, which include magnetic storage devices and optical data storage systems, utilize at least one rotatable disk with concentric data tracks containing the information, a transducer for reading data from or writing data to the various tracks, and a head positioning actuator connected to the head for moving it to the desired track and maintaining it over the track centerline during read or write operations. The transducer is attached to a head (or "slider") having an air bearing surface which is supported adjacent the data surface of the disk by a cushion of air generated by the rotating disk. The slider is attached on its back side (the side opposite the air bearing surface) to the suspension, and the suspension is attached to an actuator arm of the head positioning actuator.
The suspension provides dimensional stability between the slider and actuator arm, controlled flexibility in pitch and roll motion of the slider relative to its direction of motion on the rotating disk, and resistance to yaw motion. The suspension typically provides a load or force against the slider which is compensated by the force of the air bearing between the slider's air bearing surface and the disk surface. Thus, the slider is maintained in extremely close proximity to, but out of contact with, the data surface of the disk. The suspension typically comprises a load beam, which is mounted at one end to the actuator arm, and a flexure element which is attached to the other end of the load beam and supports the slider. The load beam provides the resilient spring action which biases the slider toward the surface of the disk, while the flexure provides flexibility for the slider as the slider rides on the cushion of air between the air bearing surface and the rotating disk. Such a suspension is described in U.S. Pat. No. 4,167,765, which is assigned to the same assignee as this application. An example of a conventional slider is described in U.S. Pat. No. 3,823,416, which is assigned to the same assignee as this application.
One type of composite or laminated structure comprising a base layer, a patterned conductive layer with patterned electrical leads formed thereon, and an insulating layer formed in between, is described in IBM Technical Disclosure Bulletin, Vol. 22, No. 4 (September, 1979), pp. 1602-1603. In this laminated suspension, the slider is epoxy bonded to the laminated suspension and the transducer leads are soldered to the electrical leads formed on the suspension.
Another laminated structure type of suspension comprised of a base layer of stainless-steel, an insulating layer of polyimide formed on the base layer, and a patterned conductive layer of etched copper alloy formed on the insulating layer, is described in U.S. Pat. No. 4,996,623. The etched copper layer provides a lead structure electrically connecting the thin-film magnetic head transducer and the disk drive's read/write electronics. A method for attaching a slider to a laminated/etched suspension in a data recording disk file has been described in U.S. Pat. No. 4,761,699 and IBM Technical Disclosure Bulletin, Vol. 36, No. 2, February, 1993.
The slider-suspension assembly (or "head-gimbal assembly" (HGA)) is an integrated unit composed of the slider being electrically and mechanically attached to the suspension. All head-gimbal assemblies on the market today use discrete wires to conduct a signal from the magnetic transducer on the slider (or "head" ) to the read/write electronics package. These wires are terminated to flex cables or electronic component cards integral to the actuator arm. In order to make this termination, the wires are positioned over termination pads residing on the flex cable or electronics package and then electrically connected to the termination pads by either a reflow soldering operation or an ultrasonic wire bond process. A majority of the disk drive industry uses a manual termination process involving skilled operators using microscopes and tweezers to place these wires individually over the termination pads. The disadvantages to this type of manual process are time, tedium and inconsistent results inherent in a manual process.
IBM uses an automated process which involves stringing the wires onto a frame that holds the wires in alignment for placement over the pads. This eliminates the variability due to a manual process. However, there are still variables due to wire tension and tolerances in the frame in its attachment to the suspension. Even without these variables, there is still the need to align the frame with its wires over the termination pads of the electronics package or flex cable. This alignment is necessary because during the assembly of the electronics package to the actuator arm there are assembly tolerances as well as component tolerances that add up to an inconsistency of where the pads are located. This inconsistency, in conjunction with wire location variables, occasionally require the robot performing the electrical terminations to make small adjustments for each wire-pad termination.
Therefore, it would be desirable to provide an improved automated process for electrically connecting the head-gimbal assembly with the actuator arm electronics package or flex cable which eliminates the tolerances introduced by a wire frame and its attachment to the suspension. It would be further desirable to provide such an automated process which can simply and accurately align the conductor lines of the head-gimbal assembly with the termination pads of the electronics package or flex cable.